This invention relates to a monogram or embroidery sewing machine for automatically forming an embroidery or stitch pattern on various kinds of workpieces such as shirts, handkerchieves, towels, etc. based on pattern information stored in memory means for storing pattern information corresponding to initials, symbols and other patterns. More particularly, it relates to an automatic sewing machine capable of forming various modified patterns or various combination patterns in accordance with the pattern information stored in the memory means.
As sewing machine of this type many automatic ones, wherein pattern information stored in memory means such as cams, punched paper tapes, etc. are simply played back, have been conventionally proposed. In the U.S. Pat. No. 2,624,302 a technology regarding "a monogramming machine capable of forming patterns of various sizes from one stencil storing pattern information corresponding to a desired pattern" is disclosed. More recently U.S. Pat. No. 4,116,144 and U.S. Pat. No. 4,122,786 respectively disclose "an automatic electronic sewing machine wherein digital pattern information stored in a static memory is temporarily stored in a dynamic memory and a part of the digital pattern information is modified by modifying means for being able to form patterns of various pattern widths" and "an automatic electronic sewing machine wherein a plurality pieces of pattern information are selected from a multitude pieces of pattern information stored in memory means for consecutively forming new combination patterns".
In those prior arts, when a combination stitch pattern consisting of two or more unit stitch patterns such as letters, symbols and other patterns is wished to be formed on a workpiece freely, varying the size of individual unit stitch patterns or the distance between individual unit stitch patterns was still beyond their capability. For forming a stitch pattern on a workpiece such that size of only one unit stitch pattern is made dissimilar from the rest or length of only one distance between the unit patterns is made dissimilar from the rest, it was necessitated in those prior arts to prepare a proper memory means such as a stencil or a paper tape for a new combination pattern corresponded to those special requirements, which was a time-consuming job as well as an enormous space requiring affair for storing the stencils and paper tapes. Another problem in the prior arts is that a trouble happening in the course of sewing operation such as thread breakage brings the needle to a somewhat away position from that where the thread breakage actually took place because of incapability of instant stopping of the machine simultaneously with the trouble happening. After the trouble has been suitable treated the operator has to manually return the needle to the actually trouble happened position when the sewing operation is recommenced or resumed and the memory means such as the stencils or paper tapes are also manually restored as far as the position corresponding to the trouble happened place.
For carrying out exactly those operations a lot of time is required, deteriorating the operation efficiency a great deal.